LINE SCAN INSPECTION
These systems are set-up to capture a single row of pixels across the product at a time and build up an image as the product is moving. This approach produces far greater results for web-based products and circular type inspections of a product. Compared to area cameras that capture the entire image in one capture, line scan cameras have the following advantages depending on the type of application.
High-quality image with uniform lighting.
Since the capture region stays the same, lighting only needs to be applied to a single area of the workpiece. This results in a more evenly lit target with fewer light sources compared to an area-type camera.
Expanded image of the side surface of a cylinder
Because the entire circumference of a cylinder can be inspected as a single image the inspection program can be set up very easily.
Extremely detailed inspection
Since the image is generated line by line in the target movement direction, a much larger pixel array can be used compared to an area camera resulting in drastically improved inspection accuracy.
Reduced inspection completion time
The XG-X Series allows inspection on fast moving lines due to high-speed camera scanning and processing.
COMPARISON OF LINE-SCAN AND AREA CAMERAS, USING REAL WORLD EXAMPLES:
(1) Visual Inspection of a Gear
Inspection using 5-megapixel area camera.
- Captures a single area of the part in one image. Three to five images (depending on the diameter) have to be taken to perform inspection of entire circumference.
- Since it is a round part, inspection is difficult due to the radius and uneven lighting.
- Multiple overlapping inspections need to be performed to analyze the entire circumference.
Inspection using line-scan camera.
- Instead of capturing multiple images, captures the image one line at a time and then expands the entire circumference into one single image.
- Lighting is very uniform and the inspection of the whole part is done in one process.
- Only one inspection cycle per part has to be performed.
- Inspection accuracy is greatly improved and processing time is reduced.
(2) Visual inspection of aluminum foil
Inspection using 5-megapixel area camera.
- Pixel array in XY direction is limited by the camera so multiple image captures may need to be performed to secure the resolution required for the inspection.
- Multiple light sources are required for even lightning over the whole surface.
- The entire workpiece is displayed but there are unnecessary void areas on the top and bottom.
Inspection using line-scan camera.
- Only the X direction pixel array is fixed based off the camera while the Y direction is expanded according to the part movement direction. Much larger pixel arrays are possible with up to 8192 × 8192 pixels (or 4096 × 16384) in one single image.
- Uniform lighting is obtained across.
- Very high detection accuracy is realized in one inspection process.
OTHER APPLICATIONS:
Inspection of pinholes and dirt on a sheet
Achieves visual inspection of foreign objects, flaws, and pinholes on film or sheets on a high-speed production line.
Appearance of pistons
The line scan camera allows various inspections of such as blowholes in the land part or irregular printing in the coated part.
Inspection of broken solar cell patterns
By using a high-pixel line scan camera to generate a detailed image of patterns printed on a solar cell, high-accuracy inspection is possible.
Fish-eye and air bubble inspections of transparent films
Bright and dark areas can be created with transmitted light in the concentrated line capture area making it possible to detect air bubbles and foreign particles which is normally difficult with standard area cameras due to uneven lighting.
Dimensional inspection of a sheet
Width measurement, which typically requires 2 area cameras on each edge, is performed with a single, high-resolution line scan camera, resulting in increased accuracy and reductions in cost.
Visual inspection of a bearing
Achieves the visual inspection of curved surfaces, which is difficult to perform with an area camera, by capturing stabilized images with even lighting.
Appearance inspection of sanitary products
The camera can be installed in a small clearance next to a conveyor to achieve various inspections for stains, smudges, or misaligned tapes.
Defect inspection of lead frames
Visual inspection of the surface of plated lead frames and plate position inspection are accurately performed during transfer.
Visual inspection of stamped material
High-speed inspection is performed on pressed parts that are continuously punched. High-speed inspection at resolutions that are much higher than conventional devices is achieved, leading to improved inspection accuracy.
Visual inspection of a roller
Defects on the surface of long metal rollers can be inspected with high-accuracy using one or two line scan cameras.
Visual inspection after printing electrodes
By using line scan cameras with line lights for targets that require a wide-field, uniform lighting is achieved and high-definition inspection is possible.
Defects on blow molded parts
Before blow molding, the entire opening and body of the part can be inspected in one image when the part is rotated.